This invention relates generally to devices and methods for aligning a photoelectric light-emitting device with a target, and more particularly to an alignment method and device for use with a conveyor.
It is well known to use photoelectric devices positioned alongside a conveyor for monitoring the movement of packages or other articles on the conveyor. Typically, the photoelectric device emits a beam of light or infrared signal across the conveyor perpendicular to the direction of motion of the conveyor. A target or reflector positioned on the opposite side of the conveyor is hit by the light or other signal and either reflects the light back to the emitting device or detects the light.
In either case, packages traveling on the conveyor will interrupt the beam of light when they pass by. The interruptions are sensed by the photoelectric device and thereby allow the packages to be monitored.
In order for the photoelectric device to operate properly, it is necessary that the beam of light, or other electromagnetic radiation, is properly pointed toward the reflector or target on the other side of the conveyor. If the photoelectric device is not properly aligned with the target/reflector, the light will miss the target/reflector and not be detected. When securing the photoelectric device to the side of the conveyor, it is therefore critical that it be precisely oriented so that the signal it emits will hit the target/reflector.
In the past, the alignment of the photoelectric emitter and the target/detector has been relatively cumbersome and difficult. In particular, past methods have required the use of two hands: one hand to hold the emitter in proper alignment and the other hand to tighten the emitter to the side of the conveyor. Additionally, the emitter must be partially tightened prior to its complete tightening in order to ensure that it does not move freely around during the alignment process. Finally, the tightening of the emitter to the side of the conveyor typically jerks the emitter around as it is tightened, rather than smoothly maintaining the desired alignment. The desirability of an alignment method or device that overcomes these disadvantages therefore can be seen.
An alignment device according to one aspect of the present invention includes a mounting plate, a fixed bracket spaced from the mounting plate, and a plurality of screws attached across the mounting plate to the fixed bracket. The screws are attached to the bracket and mounting plate in such a fashion that rotation of one or more screws alters the orientation of the mounting plate with respect to the fixed bracket. An emitter fixedly attached to said mounting plate will therefore also have its orientation altered when the screws are adjusted. The orientation of the emitter can thus be adjusted by selectively tightening or loosening one or more of the screws until the signal emitted by the emitter is properly aimed at the target or reflector.
The device and method of the present invention overcomes the disadvantages of the prior alignment techniques and devices. The present invention allows alignment of the emitter without the necessity of using two hands. Because the mounting plate, to which the emitter is fixedly secured, is already mounted to the fixed bracket, the present invention does not require holding the emitter while it is aligned. Moreover, the adjustment of the screws results in a smooth change in the orientation of the emitter, thereby alleviating the prior problem of jerky movement of the emitter. These and other benefits, objects, and results of the present invention will be apparent to one skilled in the art, in light of the following specification when read in conjunction with the accompanying drawings.